1. Field of the Invention
The present invention relates to a high heat-resistant thermoplastic resin composition which is superior in mechanical physical properties and stress crack resistance.
2. Description of the Related Art
Engineering plastics represented by polyamide, polyacetal and polyphenylene oxide resins and modifications thereof, polybutylene terephthalate resin, etc. are superior in heat resistance and strength to general-purpose resins such as polyethylene, polypropylene, polyvinyl chloride, ABS and the like. Therefore, they are widely used for applications such as automobile parts, electrical appliances, OA equipment, precision instruments, electric/electronic parts and the like.
However, most of the performance characteristics required for the various above applications can not be achieved by a single resin material. Therefore, in order to obtain a molding material which simultaneously satisfies physical properties which are contrary to each other (e.g. high impact properties and high rigidity), there is widely known a technique of blending or polymer-alloying different kinds of resins to obtain the desired physical properties.
In general, different kinds of resins are sometimes incompatible each other and, therefore, both resins form a crude phase separation structure wherein a sea/island structure is disordered in case of simply melt-kneading and the desired physical properties are sometimes not attained. Therefore, a compatibilizing agent is used for accomplishing fine dispersion of a resin component which converts into an island phase.
This compatibilizing agent is a compound or high-molecular weight material having affinity for two or more kinds of resins to be compatibilized or having a function of reacting chemically with them, and stabilizes an interface between different kinds of resins and contributes to fine dispersion of the island phase.
For example, Japanese Patent Kokai (Laid-Open) No. 56-26913 discloses that, by mixing a compound having a polar group such as carboxylic group, acid anhydride group, etc. where a polymer alloy of a polyphenylene oxide resin and polyamide is produced, a composition is obtained whose impact resistance and solvent resistance are extremely improved while the heat resistance of the polyphenylene oxide is maintained.
Japanese Patent Kokai (Laid-Open) No. 61-120855 discloses that the impact resistance and tensile elongation are extremely improved by adding a silane derivative to a polymer alloy prepared by formulating a rubber to a polyphenylene oxide resin and polyamide.
Japanese Patent Kokai (Laid-Open) No. 56-115355 discloses that a composition whose impact resistance is extremely improved is obtained by formulating a styrene-butadiene block copolymer modified with maleic anhydride to one or more engineering plastics such as polyacetal, polycarbonate and the like.
Japanese Patent Kokai (Laid-Open) No. 59-58052 discloses that the bending strength, impact resistance and hydrolysis resistance are improved by formulating an epoxy resin to a polymer alloy of a polyphenylene sulfide resin and a thermoplastic polyester resin.
In application where heat resistance is required, polymer-alloying due to combinations having high heat resistance is required. Therefore, polymer-alloying due to comparatively high heat-resistant resins, for example, polyphenylene sulfide resin and polyarylate, polysulfone, polyphenylene oxide resin, polyether ketone, thermoplastic polyimide, etc. is studied in Japanese Patent Kokai (Laid-Open) No. 59-164360. This publication discloses that the bending strength and impact resistance of a composition prepared by formulating an epoxy resin in the case of producing the polymer alloy are extremely improved in comparison with a composition prepared by formulating no epoxy resin.
However, a processing temperature exceeding 300.degree. C. is sometimes required when a polymer alloy containing such a high heat-resistant resin as a component is produced and the resulting polymer alloy composition is molded. Therefore, compounds or high-molecular weight materials formulated as the compatibilizing agent cause heat deterioration during the production of the polymer alloy or at the time of molding the resulting composition, thereby causing problems such as inhibition of a function as the compatibilizing agent, deterioration of physical properties of the composition, etc.